from collections import defaultdict as dd
from collections import deque
import bisect
import heapq

def ri():
    return int(input())

def rl():
    return list(map(int, input().split()))


def solve():
    n = ri()
    if n >= 30:
        print ("Yes")
    else:
        print ("No")





mode = 's'

if mode == 'T':
    t = ri()
    for i in range(t):
        solve()
else:
    solve() from collections import defaultdict as dd from collections import deque import bisect bisect import heapq heapq def ri():
    return int(input()) ri return int(input()) int(input()) int input() input def rl():
    return list(map(int, input().split())) rl return list(map(int, input().split())) list(map(int, input().split())) list map(int, input().split()) map int input().split() ().split () input split def solve():
    n = ri()
    if n >= 30:
        print ("Yes")
    else:
        print ("No") solve n = ri() n ri() ri if n >= 30:
        print ("Yes")
    else:
        print ("No") n >= 30 n 30 print ("Yes") print "Yes" print ("No") print "No" mode = 's' mode 's' if mode == 'T':
    t = ri()
    for i in range(t):
        solve()
else:
    solve() mode == 'T' mode 'T' t = ri() t ri() ri for i in range(t):
        solve() i range(t) range t solve() solve solve() solve mode = 's' 's' mode t = ri() ri() t def solve():
    n = ri()
    if n >= 30:
        print ("Yes")
    else:
        print ("No") def solve():
    n = ri()
    if n >= 30:
        print ("Yes")
    else:
        print ("No") solve def ri():
    return int(input()) def ri():
    return int(input()) ri def rl():
    return list(map(int, input().split())) def rl():
    return list(map(int, input().split())) rl
from collections import defaultdict as dd
from collections import deque
import bisect
import heapq

def ri():
    return int(input())

def rl():
    return list(map(int, input().split()))


def solve():
    n = ri()
    if n >= 30:
        print ("Yes")
    else:
        print ("No")





mode = 's'

if mode == 'T':
    t = ri()
    for i in range(t):
        solve()
else:
    solve()
